Microsoft® Exchange Server 2010 Inside Out

Dealing with I/O

Even though the type and volume of email had changed dramatically since Microsoft first laid out Exchange’s database schema in 1996, Exchange Server 2000, 2003, and 2007 use the same schema that emphasizes efficient storage over utility. Cheaper storage makes it less attractive to focus on storage efficiency. To achieve a reduction in I/O, the Store had to move away from forcing disks to do many small random I/Os to fetch data, instead using larger sequential I/Os. The physical performance difference between random and sequential I/O almost guarantees better performance and lower I/O activity for any application if the code is written to move away from random I/O. To make the change, Exchange 2010 introduces a new schema (discussed ...